1/*
2** Garbage collector.
3** Copyright (C) 2005-2014 Mike Pall. See Copyright Notice in luajit.h
4*/
5
6#ifndef _LJ_GC_H
7#define _LJ_GC_H
8
9#include "lj_obj.h"
10
11/* Garbage collector states. Order matters. */
12enum {
13 GCSpause, GCSpropagate, GCSatomic, GCSsweepstring, GCSsweep, GCSfinalize
14};
15
16/* Bitmasks for marked field of GCobj. */
17#define LJ_GC_WHITE0 0x01
18#define LJ_GC_WHITE1 0x02
19#define LJ_GC_BLACK 0x04
20#define LJ_GC_FINALIZED 0x08
21#define LJ_GC_WEAKKEY 0x08
22#define LJ_GC_WEAKVAL 0x10
23#define LJ_GC_CDATA_FIN 0x10
24#define LJ_GC_FIXED 0x20
25#define LJ_GC_SFIXED 0x40
26
27#define LJ_GC_WHITES (LJ_GC_WHITE0 | LJ_GC_WHITE1)
28#define LJ_GC_COLORS (LJ_GC_WHITES | LJ_GC_BLACK)
29#define LJ_GC_WEAK (LJ_GC_WEAKKEY | LJ_GC_WEAKVAL)
30
31/* Macros to test and set GCobj colors. */
32#define iswhite(x) ((x)->gch.marked & LJ_GC_WHITES)
33#define isblack(x) ((x)->gch.marked & LJ_GC_BLACK)
34#define isgray(x) (!((x)->gch.marked & (LJ_GC_BLACK|LJ_GC_WHITES)))
35#define tviswhite(x) (tvisgcv(x) && iswhite(gcV(x)))
36#define otherwhite(g) (g->gc.currentwhite ^ LJ_GC_WHITES)
37#define isdead(g, v) ((v)->gch.marked & otherwhite(g) & LJ_GC_WHITES)
38
39#define curwhite(g) ((g)->gc.currentwhite & LJ_GC_WHITES)
40#define newwhite(g, x) (obj2gco(x)->gch.marked = (uint8_t)curwhite(g))
41#define makewhite(g, x) \
42 ((x)->gch.marked = ((x)->gch.marked & (uint8_t)~LJ_GC_COLORS) | curwhite(g))
43#define flipwhite(x) ((x)->gch.marked ^= LJ_GC_WHITES)
44#define black2gray(x) ((x)->gch.marked &= (uint8_t)~LJ_GC_BLACK)
45#define fixstring(s) ((s)->marked |= LJ_GC_FIXED)
46#define markfinalized(x) ((x)->gch.marked |= LJ_GC_FINALIZED)
47
48/* Collector. */
49LJ_FUNC size_t lj_gc_separateudata(global_State *g, int all);
50LJ_FUNC void lj_gc_finalize_udata(lua_State *L);
51#if LJ_HASFFI
52LJ_FUNC void lj_gc_finalize_cdata(lua_State *L);
53#else
54#define lj_gc_finalize_cdata(L) UNUSED(L)
55#endif
56LJ_FUNC void lj_gc_freeall(global_State *g);
57LJ_FUNCA int LJ_FASTCALL lj_gc_step(lua_State *L);
58LJ_FUNCA void LJ_FASTCALL lj_gc_step_fixtop(lua_State *L);
59#if LJ_HASJIT
60LJ_FUNC int LJ_FASTCALL lj_gc_step_jit(global_State *g, MSize steps);
61#endif
62LJ_FUNC void lj_gc_fullgc(lua_State *L);
63
64/* GC check: drive collector forward if the GC threshold has been reached. */
65#define lj_gc_check(L) \
66 { if (LJ_UNLIKELY(G(L)->gc.total >= G(L)->gc.threshold)) \
67 lj_gc_step(L); }
68#define lj_gc_check_fixtop(L) \
69 { if (LJ_UNLIKELY(G(L)->gc.total >= G(L)->gc.threshold)) \
70 lj_gc_step_fixtop(L); }
71
72/* Write barriers. */
73LJ_FUNC void lj_gc_barrierf(global_State *g, GCobj *o, GCobj *v);
74LJ_FUNCA void LJ_FASTCALL lj_gc_barrieruv(global_State *g, TValue *tv);
75LJ_FUNC void lj_gc_closeuv(global_State *g, GCupval *uv);
76#if LJ_HASJIT
77LJ_FUNC void lj_gc_barriertrace(global_State *g, uint32_t traceno);
78#endif
79
80/* Move the GC propagation frontier back for tables (make it gray again). */
81static LJ_AINLINE void lj_gc_barrierback(global_State *g, GCtab *t)
82{
83 GCobj *o = obj2gco(t);
84 lua_assert(isblack(o) && !isdead(g, o));
85 lua_assert(g->gc.state != GCSfinalize && g->gc.state != GCSpause);
86 black2gray(o);
87 setgcrefr(t->gclist, g->gc.grayagain);
88 setgcref(g->gc.grayagain, o);
89}
90
91/* Barrier for stores to table objects. TValue and GCobj variant. */
92#define lj_gc_anybarriert(L, t) \
93 { if (LJ_UNLIKELY(isblack(obj2gco(t)))) lj_gc_barrierback(G(L), (t)); }
94#define lj_gc_barriert(L, t, tv) \
95 { if (tviswhite(tv) && isblack(obj2gco(t))) \
96 lj_gc_barrierback(G(L), (t)); }
97#define lj_gc_objbarriert(L, t, o) \
98 { if (iswhite(obj2gco(o)) && isblack(obj2gco(t))) \
99 lj_gc_barrierback(G(L), (t)); }
100
101/* Barrier for stores to any other object. TValue and GCobj variant. */
102#define lj_gc_barrier(L, p, tv) \
103 { if (tviswhite(tv) && isblack(obj2gco(p))) \
104 lj_gc_barrierf(G(L), obj2gco(p), gcV(tv)); }
105#define lj_gc_objbarrier(L, p, o) \
106 { if (iswhite(obj2gco(o)) && isblack(obj2gco(p))) \
107 lj_gc_barrierf(G(L), obj2gco(p), obj2gco(o)); }
108
109/* Allocator. */
110LJ_FUNC void *lj_mem_realloc(lua_State *L, void *p, MSize osz, MSize nsz);
111LJ_FUNC void * LJ_FASTCALL lj_mem_newgco(lua_State *L, MSize size);
112LJ_FUNC void *lj_mem_grow(lua_State *L, void *p,
113 MSize *szp, MSize lim, MSize esz);
114
115#define lj_mem_new(L, s) lj_mem_realloc(L, NULL, 0, (s))
116
117static LJ_AINLINE void lj_mem_free(global_State *g, void *p, size_t osize)
118{
119 g->gc.total -= (MSize)osize;
120 g->allocf(g->allocd, p, osize, 0);
121}
122
123#define lj_mem_newvec(L, n, t) ((t *)lj_mem_new(L, (MSize)((n)*sizeof(t))))
124#define lj_mem_reallocvec(L, p, on, n, t) \
125 ((p) = (t *)lj_mem_realloc(L, p, (on)*sizeof(t), (MSize)((n)*sizeof(t))))
126#define lj_mem_growvec(L, p, n, m, t) \
127 ((p) = (t *)lj_mem_grow(L, (p), &(n), (m), (MSize)sizeof(t)))
128#define lj_mem_freevec(g, p, n, t) lj_mem_free(g, (p), (n)*sizeof(t))
129
130#define lj_mem_newobj(L, t) ((t *)lj_mem_newgco(L, sizeof(t)))
131#define lj_mem_newt(L, s, t) ((t *)lj_mem_new(L, (s)))
132#define lj_mem_freet(g, p) lj_mem_free(g, (p), sizeof(*(p)))
133
134#endif
135